Slack adjuster



g 1951 D. J. PRITCHARD SLACK ADJUSTER Filed June 28, 1947 fizz INVENTOR, 36 Jj zj'zyaz'xz" J Patented Aug. 14, 1951 SLACK ADJUSTER Donald J. Pritchard, San Diego, Calif., assignor to American Steel Foundries, Chicago, 111., a corporation of New Jersey Application June 28, 1947, Serial No. 757,835

14 Claims. 1

This invention relates to brake rigging and more particularly to a slack adjuster which is adapted for use with such rigging.

The type of slack adjuster with which the present invention is concerned comprises 'a fulcrum block slidably mounted within a tie rod or brake rod frame, the block comprising oppositely arranged guiding flanges and oppositely arranged grooves, the flanges underlying the sides of the frame and the grooves receiving the legs of a U-shaped retainer plate therein, said legs overlying the upper surfaces of said sides of the frame and in cooperation with said flanges interlocking said block with the frame. The usual objection to this arrangement is that the retainer plate and block must be placed in tandem for assembling and disassembling the same which necessitates the provision of a long frame. The principal object of this invention is to devise a slack adjuster of the type described wherein the fulcrum blocl: and retainer plate are so arranged that the same may be easily and quickly assembled and disassembled without placing the parts in tandem within the tie rod frame and without distorting any of the parts thus permitting a substantial reduction in the length of the frame with resultant saving of metal and space.

Another object of the invention is to devise a fulcrum block and a retainer plate of novel form which may be easily and readily assembled and disassembled.

These and other objects will be apparent from the specification and the drawings, wherein:

Figure l is a top plan View, partly in horizontal section, of a slack adjuster constructed in accordance with the present invention;

Figure 2 is a side elevation of the same;

Figure 3 is a front end view of the fulcrum block assembly;

Figure 4 is a top plan view of the novel retainer plate; Figure 5 is a front end view of the plate; and Figure 6 is a fragmentary rear end view of the upper portion of the block.

Referring to the drawings in detail, it will be noted that the slack adjuster is mounted at one end of a brake rod 2, having an open frame 4 with spaced sides 6, 5 which are joined at the ends opposite the rod by a hub 8. The slack adjuster includes a U-shaped fulcrum block, generally designated Id, received between the sides 6, 6 for slidable movement within the frame longitudinally of the rod. The fulcrum block comprises a head 52 and spaced arms I 4, I 4 extending parallel to the sides 6, 6 of the frame,

said arms being connected at corresponding ends to the opposite sides of the head l2. The lower portion of the block is provided with coplanar laterally outwardly extending flanges [6, I5 which slidably engage the undersurfaces of the sides 5, l; of the frame 4.

The upper portion ofthe block In extends above the upper edges of the sides 6, 6 of the frame 4 and is provided with oppositely arranged grooves l8, 18 formed in the remote sides of the arms l4, [4, said grooves extending longitudinally of the arms parallel to the flanges i6, i6 and being defined by laterally extending shoulders 20 and laterally extending spaced coplanar flanges or projections 22, 22 overlying said shoulders and vertically spaced therefrom, the flanges and shoulders being formed at the upper edges of said arms adjacent the upper surfaces of the sides 6, 6 of the frame. The rear flanges 22, 22 disposed adjacent the head of the block are integrally connected by a flange 24 formed on said head, said flange 24 partially defining a groove 28 (Figure 3) formed in said head coplanar With and connected at opposite ends to said grooves l8, It in said arms.

The longitudinally spaced flanges 22, 22 on each arm define a channel or recess 30 therebetween intermediate the ends of the block. The recesses 36, 3!] in the opposite sides of the block extend to the top of the block transversely of the grooves l8, l8 and communicate therewith for a purpose hereinafter described.

To interlock the block [0 with the frame, a U-shaped yoke or retainer plate 32 is provided having longitudinally extending legs 34, 34 with inwardly extending lugs or projections 3t, 36 at their ends received in the grooves l8, l8, said legs being connected at corresponding ends by a crosspiece or bridge member 38 received in the groove 23 in said head. The laterally extending flanges l8, l6 and the legs 34, 34 respectively form the upper and lower guides for the fulcrum block of the slack adjuster in slidably engaging the upper and lower surfaces of the sides 6, 6 of the frame i and cooperatively interlock the block with the frame.

The arms M, i i of the block IE3 at the ends remote from the head of the block are provided with transverse aligned openings 40, 4f] for reception of a lever fulcrum pin 42 affording a pivotal connection for a brake lever (not shown) in the usual manner.

For effecting adjustment of the fulcrum block. It, an elongated screw 44 is provided, having an inwardly projecting end 45 fitting into a socket 48 formed centrally in the head of the fulcrum 3 block, and by means of a bolt or pin 53 the block, the screw, and the retainer plate are secured together, the flange 24 being relieved as at 52 (Figure 1) to accommodate seating the head of the bolt on the crosspiece of the retainer plate.

A nut 54 is threaded on the outer end of the screw Ml, said nut being rotatably mounted within the hub 8 and having a shoulder or enlarged end 56 engaging the inner surface of the hub 3 and being provided with an extension having a seating portion 58 and a plurality of flat surfaces 6H, 60 (Figure 2) whereby the same may be easily gripped by any suitable tool for rotating the nut and thus adjusting the position of the fulcrum block by retractin or extending the screw M, as will be readily understood by those skilled in the art.

For preventing endwise movement of the nut 54 a collar 62 is suitably secured to the seating portion 58 of the extension,the collar engaging the outside surface of the hub 8 and thus, in connection with the enlarged end 56 of the nut, serves to hold the nut in position in the hub against any tension exerted by the fulcrum block. A grease fitting 64 may be fitted in the hub 8 for lubricating the nut.

The collar 62 is provided with a series of recesses 66, 6B (Figure 1) formed on the inner surface of the collar, said recesses being adapted to cooperate with ball catch means 68 (Figure 1) mounted in a pocket 10 in the hub 8 to releasably hold the nut against unwanted rotation.

To assemble my novel slack adjuster the nut is inserted into the hub. The catch means are then mounted in the pocket 10 in the hub. The collar is then secured to the nut. The screw 44 is threaded into thenut, The brake lever (not shown) is then placed between the arm I4, Id of the block, and the fulcrum pin is inserted through the lever and into the openings 40, G0 in the arms of the fulcrum block. The block ID, with the brake leverand pin in position, is placed into the frame either by raising the parts with respect to, the frame or lowering the frame upon said parts. 7 Upon the block having been placed into the frame, the flanges l6, l6 seat against the lower surfaces of the sides 6, 6. The retainer plate is next interlocked with the fulcrum block. This is accomplished aligning the rear flanges 22, 22 between the forward and rear lugs 36, 36 on the legs 34, 34 of the retainer plate. The retainer plate is moved downwardly past the flanges 22, 22 (the forward projections 35, 36 on the legs 34, 34 of the retainer plate passing through channels 35), 39 in opposite sides of the fulcrum block) and is seated on the shoulders 20, 20. In such position the legsof the retainer plate and lugs 36, 33 are aligned with the grooves I8, 18 and to interlock the retainer plate with the block the lugs 36, 36 are caused to dovetail with the projections forming the flanges 22, 22 by moving the plate longitudinally forwardly of the block until said lugs 36, 36 enter the grooves l8, l8 and the crosspiece of said plate enters the groove 28 in the head. It will be observed that the plate and block need not be placed in tandem, thus obviating the necessity of a long frame. The slack adjuster with the brake lever is then moved toward the screw 44 until the inner end of the screw enters the socket 48 in the head of the block. The bolt 50is then inserted through aligned openings in the crosspiece of the retainer plate in the head and in the inner end of the screw 44, thus securing the retainer plate, the block and the screw in assembled relation. A nut 12 is channels threaded on the end of the bolt 50 and is secured thereon by a cotter key 14. The application of the grease fitting 64 to the hub 8 completes the assembly of the slack adjuster.

It is to be understood that I do not wish to be limited by the exact embodiment of the device shown which is merely by way of illustration and not limitation as variousand other forms of the device will, of course, be apparent to those skilled in the art without departing from the spirit of the invention or the scope of the claims.

I claim: a

1. A slack adjuster arrangement including in combination an adjuster jaw and a lever-carrying adjuster block slidably and guidedly mounted therein, said blockhaving lateral flanges at the lower portion thereof slidably engaging the underside of said jaw, a retainer plate having a slot therein with oppositely directed projections extending into said slot, oppositely arranged grooves in the upper portion of said block, recesses in said upper portion of said block communicating with said grooves and adapted to afford clearance for said projections upon insertion of said plate onto said block over the upper portion thereof to permit entry of said projections into said grooves for interlocking said plate and member, said plate overlying said jaw and with said flanges embracing said jaw therebetween, thus interlocking said block and jaw.

2. In a brake slack adjuster, the combination of a frame and brake lever fulcrum means adjustably mounted therein and comprising a lever carrying element having laterally extending flanges engaging said frame and having oppositely arranged grooves parallel to said'flanges, oppositely arranged recesses in' said member disposed transversely of said grooves and communicating therewith, and a retainer plate comprising spaced legs with oppositely arranged projections insertable through said recesses into said grooves for interlocking said plate with said element, the legs of said plate slidably engaging said frame and with, said flanges embracing said frame therebetween, thereby interlocking said element and frame.

3. In a slack adjuster, a frame, a lever-carrying element slidably and adjustably mounted in said frame and comprising means slidably engaging a portion of said frame, and means cooperable with said first-mentioned means andinterlo'cked with said block and slidably engaging an opposite portion of said frame, said last-mentioned means comprising a U-shaped yoke with spaced legs embracing said block therebetween, said legs having inwardly extending projections received within complementary grooves in said element extending to said grooves transversely of said frame to accommodate assembly and disassembly of said yoke with said block by permitting ingress and egress of said projections to and from said grooves.

4. In a brake slack adjuster, a frame, a fulcrum block slidably and adjustably. mounted therein and having flanges seated against one side of said frame, and means cooperable with said flanges for interlocking said block and frame and comprising a member having spaced legs with inwardly extending projections received within oppositely'arranged'grooves in' said block, said legs being seated against the opposite side of said'frame, and recesses in said block extending to said grooves and affording a passagefor said projections to and from said grooves for acin said element, and

commodating assembly and disassembly of said member with said block.

5. In a slack adjuster, a frame, a fulcrum block slidably and adjustably mounted therein and means for interlocking said block and frame comprising lateral flanges on said block engaging one side of said frame, a retainer member insertable over said block and comprising oppositely arranged projections received within grooves in said block, and channels communicating with said grooves at points intermediate the ends thereof and extending upwardly of said block, said projections being alignable with said channels upon removal thereof from said grooves, whereby assembly and disassembly of said member with respect to said block is accommodated.

6. A slack adjuster comprising a frame, a levercarrying block received therein and slidably engaged with one side thereof for relative movement longitudinally of said frame, spaced projections at each side of said block, retainer means comprising spaced portions slidably engaging the opposite side of said frame to retain the block in said frame, and spaced lugs on each portion engaging the inner surfaces of the associated projections and adapted to dovetail therewith during assembly and disassembly of said retainer means, and means for adjusting the position of said block in said frame.

7. In a brake slack adjuster, the combination of a frame, a fulcrum block slidably mounted in said frame and comprising lateral flanges slidably engaging said frame and having grooves in opposite sides thereof, a retainer member having legs extending the length of said block and having inwardly extending projections insertable into said grooves through recesses in said block communicating with said grooves, said legs slidably engaging another portion of said frame and with said flanges embracing said frame, thus interlocking said block therewith.

8. A slack adjuster subassembly comprising a fulcrum member, retainer means for interlocking said member with an associated structure, a plurality of elements on said member spaced longitudinally thereof, and a plurality of spaced lugs on said retainer means disposed one beneath each element for locking said retainer means with said member, said elements and lugs being separable through the spaces therebetween when misaligned with each other, said elements 'extending laterally from opposite sides of said member and said retainer means extending outwardly laterally of said member.

- 9. A slack adjuster fulcrum member comprising a block with a lever slot therein and having a groove and recess in opposite sides thereof, each groove extending longitudinally of the block and the associated recess communicating therewith intermediate the ends thereof and being open through another side of said block, and retainer flanges at said opposite sides of the block remote from said last-mentioned side and extending generally parallel to said grooves.

10. A slack adjuster fulcrum block having a lever slot and having a recess and groove in opposite sides thereof, said grooves extending longitudinally of the block, and said recesses extending angularly with respect to said grooves and open at one end to another side of said block and each communicating at its other end with the associated groove intermediate the ends thereof.

11. A slack adjuster fulcrum member compris-= ing a block having spaced arms and a head interconnecting said arms and defining a lever slot therewith, shoulders and flanges on the remote sides of said arms formed and arranged to define grooves extending longitudinally of said block, the flanges on each arm being spaced longitudinally thereof and defining a channel with the adjacent portion of the related arm, said channel communicating with the associated groove intermediate the ends thereof and extending to a lateral edge of the associated arm.

12. A slack adjuster fulcrum member comprising a block having spaced arms and a head interconnecting said arms and defining a lever slot therewith, shoulders and flanges on the remote sides of said arms adjacent one of the lateral edges thereof formed and arranged to provide grooves extending longitudinally of said arms and recesses extending from said lateral edges of said arms, each recess communicating with an adjacent groove intermediate the ends thereof.

13. A slack adjuster subassembly comprising a fulcrum member, a retainer member for interlocking said fulcrum member with an associated structure, and pairs of interengaging elements on said members for interlocking the same, said pairs being spaced from each other longitudinally of said fulcrum member, one of the elements of each pair being on the fulcrum member and the other of the elements of each pair being on said retainer member, said members being movable longitudinally of each other to disengage the elements of each pair whereby the elements on one member are caused to be positioned in alternating relation longitudinally of said members with the elements on the other members, whereby in the disassembly and assembly of said members said elements are accommodated passage between each other, the elements on the fulcrum member projecting outwardly from opposite sides thereof and the elements on said retainer extending inwardly thereof.

14. A slack adjuster comprising a frame, lever carrying means movably mounted within the frame, and means for interlocking said lever carrying means with the frame and comprising a plurality of projections at each side of said lever carrying means and carried thereby, retainer means slidably engaging the frame and having a plurality of lugs at each side of the frame overlapping the inner surfaces of the related projections, said projections being spaced from each other and the lugs being spaced from each other in such manner as to accommodate passage of the lugs between the projections when the lugs and projections are misaligned during the assembly and disassembly of said means.

DONALD J. PRITCHARD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,668,124 Pfeiffer May 1, 1928 1,786,978 Aronson Dec. 30, 1930 2,245,778 Handke June 17, 1941 2,413,971 Heintz Jan. 7, 1947 

